Interpretive Summary: Most plant viruses are transmitted by insects, such as aphids and whiteflies. These insects transit plant virus from plant to plant in similar ways, suggesting that the control mechanisms regulating virus transmission is conserved among different insect vector taxa. The viruses they transmit cause significant economic loss to disease in all major staple and fruit crops. There are few consumer accepted cultivars with effective virus resistance. Cultural control practices depend upon controlling or avoiding vector insect populations as a way to reduce the spread of the virus into and within the crop. Previously, we reported a panel of biomarkers that can predict aphid populations that transmit virus with high efficiency. Here we explore whether these biomarkers are found in other aphid species and other insect taxa, such as whiteflies, to expand our understanding of virus transmission by insects and the utility of these biomarkers as a pest management tool for helping to target vector populations for control. We demonstrate that the biomarkers are conserved in multiple aphid species and in whiteflies. Furthermore, we use a highly innovative mass spectrometry approach to prove that the biomarkers are expressed in the insects. These data provide the proof of principle that a pest management strategy based in biomarker technology is possible for multiple taxa of insect disease vectors.

Technical Abstract:
Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent, circulative manner by homopteran insects. Using fluorescence 2-D difference gel electrophoresis to compare the proteomes of genotypes in an F2 population of S. graminum that segregated for virus transmission ability we recently discovered a panel of protein biomarkers that predict vector competency. Here we used aphid and whitefly nucleotide and expressed sequence tag database mining to test whether thse biomarkers are conserved in other homopteran insects. In species with available nucleotide sequence, we discovered gene homologs that shared a high degree of predicted amino acid identify in two other aphid species and in the whitefly Bemisia tabaci. Selective reaction monitoring mass spectrometry was used to validate the expression of these biomarkers proteins in multiple aphid vector species. The conservation of these proteins in multiple insect taxa that transmit plant viruses along the circulative transmission pathway creates the opportunity to use these biomarkers in a field-based assay to rapidly identify insect populations that are the most efficient vectors and allow them to be targeted for control prior to the spread of virus within a crop.